feat: 二级页面色彩刷新 + 用药/通知/设备重构 + 后端健康档案/通知管线增强 + 大量测试

## 后端
- 健康档案: 新增手术状态字段 + EF 迁移; HealthArchiveService 新增查询方法
- 健康记录: HealthRecordService 新增批量/统计方法; 契约扩展
- 用药: 新增 MedicationScheduleStatus 枚举; MedicationService 排班逻辑调整
- 通知: EfUserNotificationPipeline 重构; 新增 EfReminderCatchUpService; 通知管线支持更多场景
- 用户: UserService 账号删除逻辑; 新增 local_account_file_cleanup; EfUserRepository 扩展
- AI: medication_agent_handler 微调; prompt_manager 优化; AiConversationService 上下文处理
- Endpoint: doctor/medication/exercise/health/notification/user 等多接口调整
- BackgroundService: health_record_reminder_service 重构, 提醒补漏逻辑
- 测试: 新增 account_deletion/doctor_endpoint/medication_schedule/medication_update/prompt_manager 测试

## 前端
- UI 系统: app_theme 大幅重构; app_colors/app_design_tokens/app_module_visuals 调整; 二级页面色彩刷新
- 主页: home_page 背景渐变 + 消息列表提取 _HomeMessages + 通知检查逻辑; chat_messages_view 全面重构
- 用药: medication_list/edit/checkin 三页重构, 新增 medication_ui_logic 抽取
- 通知: notification_prefs_page 重构, 新增 notification_prefs_logic; notification_center 优化
- 设备: device_management 重构, 新增 device_sync_ui_logic; device_scan 优化
- 趋势图: trend_page 大幅重构
- 登录: login_page 重构
- 个人资料: 新增 profile_edit_page; profile_page 优化
- 运动: 新增 exercise/ 目录 + care_plan_ui_logic
- 其他: remaining_pages/report_pages/health_drawer/admin/doctor 等多页面调整
- 组件: common_widgets/app_empty_state/app_error_state/app_future_view/app_toast/ai_content 优化
- Provider: chat_provider/consultation_provider/data_providers/auth_provider 调整
- AndroidManifest: 移除多余权限
- 测试: 新增 ai_content/care_plan/home_message/login_flow/medication_checkin/medication_ui/notification_prefs/profile_device/secondary_page/swipe_delete 等大量测试

## 文档
- 新增 ui-design-system.md 设计系统文档
- 新增 secondary-page-color-refresh 计划 + specs 目录

health_app/lib/widgets/app_empty_state.dart

@@ -1,12 +1,14 @@
 import 'package:flutter/material.dart';
 import '../core/app_colors.dart';
-import 'app_gradient_widgets.dart';
 
 class AppEmptyState extends StatelessWidget {
   final IconData icon;
   final String title;
   final String? subtitle;
   final Widget? action;
+  final Color iconColor;
+  final Color? iconBackground;
+  final EdgeInsetsGeometry padding;
 
   const AppEmptyState({
     super.key,
@@ -14,32 +16,34 @@ class AppEmptyState extends StatelessWidget {
     required this.title,
     this.subtitle,
     this.action,
+    this.iconColor = AppColors.primaryDark,
+    this.iconBackground,
+    this.padding = const EdgeInsets.all(48),
   });
 
   @override
   Widget build(BuildContext context) {
     return Center(
       child: Padding(
-        padding: const EdgeInsets.all(48),
+        padding: padding,
         child: Column(
           mainAxisSize: MainAxisSize.min,
           children: [
             Container(
-              width: 80,
-              height: 80,
+              key: const ValueKey('empty-state-icon-surface'),
+              width: 72,
+              height: 72,
               decoration: BoxDecoration(
-                gradient: AppColors.softGlassGradient,
-                borderRadius: BorderRadius.circular(40),
-                border: Border.all(color: AppColors.borderLight),
-                boxShadow: AppColors.cardShadowLight,
+                color: iconBackground ?? iconColor.withValues(alpha: 0.09),
+                shape: BoxShape.circle,
               ),
-              child: AppGradientIcon(icon: icon, size: 34),
+              child: Icon(icon, size: 32, color: iconColor),
             ),
-            const SizedBox(height: 18),
+            const SizedBox(height: 16),
             Text(
               title,
               style: const TextStyle(
-                fontSize: 18,
+                fontSize: 17,
                 fontWeight: FontWeight.w700,
                 color: AppColors.textPrimary,
               ),